ISO 898-5:2012

Overview

ISO 898-5:2012 defines the mechanical and physical properties of set screws and similar threaded fasteners made of carbon steel and alloy steel, with emphasis on specified hardness classes for both coarse thread and fine pitch thread. Tests are specified for fasteners evaluated at ambient temperatures (10 °C to 35 °C), and the standard classifies fasteners by hardness (e.g., 14H, 22H, 33H, 45H) where the numeric part equals one‑tenth of the minimum Vickers hardness (HV).

Key topics and technical requirements

• Scope: Applies to ISO metric triangular threads (ISO 68‑1) for coarse threads M1.6 to M30 and fine threads M8×1 to M30×2, with pitch/diameter and tolerance conformity to ISO 261/262 and ISO 965‑1/2.
• Hardness classes & designation: Classes 14H, 22H, 33H, 45H (Vickers HV minima: 140, 220, 330, 450 respectively).
• Materials and heat treatment: Permits carbon and alloy steels, typically quenched and tempered for higher classes; case hardening is not allowed. Table-based chemical composition limits guide material selection.
• Mechanical/physical properties: Performance hardness, surface hardness limits, non‑carburization and decarburization depth controls, and surface integrity requirements.
• Test methods: Prescribes hardness testing (Vickers, Brinell, Rockwell per ISO 6507/6506/6508), decarburization and carburization assessment, and specific tests such as proof torque for hexagonal/hexalobular socket set screws of certain hardnesses.
• Inspection and conformance: Roles defined for manufacturer, supplier and purchaser inspection; in disputes, Clause 9 test methods apply.
• Marking & documentation: Requirements for manufacturer identification, hardness class marking and package labeling.
• Usage temperature guidance: Fasteners conforming to ISO 898‑5 are commonly used between –50 °C and +150 °C; users should consult metallurgists for extreme temperatures up to +300 °C.

Practical applications and users

ISO 898-5:2012 is essential for:

• Fastener manufacturers establishing production and quality-control processes for set screws and similar threaded fasteners.
• Design and mechanical engineers specifying hardenable set screws for assemblies under compressive stress.
• Quality assurance and inspection teams performing hardness, decarburization and surface integrity tests.
• Procurement professionals specifying compliance and marking requirements in purchase orders. Common industries: automotive, machinery, electronics, and other sectors where secure, hardness‑classified set screws are used.

Related standards

• ISO 68‑1 (metric screw threads)
• ISO 261 / ISO 262 (thread pitch and diameter)
• ISO 965‑1 / ISO 965‑2 (thread tolerances)
• ISO 6506‑1, ISO 6507‑1, ISO 6508‑1 (Brinell/Vickers/Rockwell hardness tests)
• ISO 6157‑1 (surface integrity)

Keywords: ISO 898-5:2012, set screws, threaded fasteners, hardness classes, coarse thread, fine pitch, mechanical properties, carbon steel, alloy steel, hardness testing.